One of the reasons that second hand smoke is considered worse than direct smoking is that the smoker is inhaling through a filter (usually) and the second hand recipient isn't. Also there are other dangers to that than just lung cancer. I lived with an asthmatic for 7 years and during that time I worked in a dog grooming shop with 3 or 4 others who were chain smokers. I didn't smoke and never have because my father died of emphysema. When Gene moved in with me just the smoke residue on my clothes and purse would irritate his lungs. I would come home and bag my purse and my dirty clothes and shower immediately. After doing this for a few weeks I began to notice how much less my own home smelled of smoke and no one had smoked in my apartment at all. When I moved to Florida and worked in a non smoking environment my own health improved as in I got fewer respiratory illnesses and my sinus problems subsided tremendously. To give you an idea of how bad the smoke was in the grooming shop every surface had been yellowed with tobacco stains.
Dana